Multiple cell wall blebs were observed on the surface of three strains of N. meningitidis taken from log phase cultures. The blebs originated as evaginations of the outer layer of the cell wall. Bleb production was noted on both defined or complex media either as broth or a solid medium. The addition of 10% normal bovine serum to the various media did not affect the production and release of these surface blebs. However, as broth cultures progressed into the stationary phase of growth, the blebs disappeared from the surface of the cells. Blebs were present in substantial quantities in culture supernatant fluids and on cell surfaces and were readily isolated by ultracentrifugation. Analysis for 2-keto-3-deoxyoctonate in cultures revealed that 18% of the total endotoxin of log phase cultures was present in blebs from the cell wall.

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The nasopharynx of known meningococcal carriers without signs of acute meningococcal disease as well as cerebrospinal fluid from patients with acute meningococcal disease were cultured on Thayer-Martin agar. Pili were observed in negatively stained preparations of over 80% cells from all primary cultures of both nasopharnyx and cerebrospinal fluids. Although pili were abundant on cells from all primary cultures, all pili were lost on serial subculture in the laboratory. This loss of pili from the cell surface on laboratory subculture was not accompanied by a concomitant loss of cell wall blebs.

The 38,200-molecular weight (unreduced)/41,900-molecular-weight (reduced) glycoprotein of bovine rotavirus, isolate C486, was identified as the major neutralizing antigen. This glycoprotein as well as the corresponding glycoprotein of another bovine rotavirus serotype also specifically attached to cell monolayers under normal conditions for virus adsorption in vitro. Further support for this glycoprotein being directly responsible for virus attachment to cells was that (i) infectious virus of both serotypes could compete with the C486 glycoprotein for cell surface receptors, and (ii) neutralizing monospecific antiserum and neutralizing monoclonal antibodies directed toward the glycoprotein could block this virus-cell interaction. Preliminary epitope mapping of the glycoprotein with monoclonal antibodies further localized the neutralization-adsorption domain to a peptide with an approximate molecular weight of 14,000. The effect of two protein modifications, glycosylation and disulfide bridging, on the reactivity of this peptide with antibodies and cell surface receptors was investigated. It was demonstrated that, whereas glycosylation did not appear to affect these reactivities, disulfide bridging seemed to be essential.